1. Field of the Invention
The present invention concerns a device to transfer high frequency electrical signals between a rotating component and a stationary component, which includes a rotor; a stator; at least one brush with a number of electrically conductive fibers attached at the stator, the fibers establishing a sliding contact with the rotor; and a slideway arranged to the side of the rotor and facing toward the stator, on which the fibers of the at least one stator-side brush rest.
2. Description of the Prior Art
Devices that are used to transfer high frequency electrical signals are known, such as plate slip rings that essentially represent a rotating connection. In the following, the designation “slip ring” is also used for these types of connections. These slip rings are produced in various sizes; their diameters range from a few millimeters to nearly two meters for computed tomography. Slip rings can be used, for example, to transfer the digital image data and also to supply power to the x-ray source.
High frequency signals or currents can be transferred between a static component and a rotating component (thus between stator and rotor) with these rotating connections. In general, the stator together with one or more brushes (made from very thin, electrically conductive fibers, for example from silver) forms a sliding contact with the rotor, wherein the brush contacts touch the slideway of the rotor at their ends and thus establish the contact. For example, this is known from U.S. Pat. No. 7,105,983 B2.
In this patent, a slip ring to establish an electrical contact between a stator and a rotor is described, wherein the stator has a current-conducting conductor with a fiber bundle formed by individual fibers, the ends of which point toward the stator are fixed in a brush tube. The other end of the fiber bundle rests on the rotor and thus forms the sliding contact. Furthermore, a collimator tube is provided that surrounds the fiber bundle at its transition to the brush tube and thus should at least partially reinforce the fibers in order to prevent bending of the fibers that is too severe given a rotation of the rotor.
In the known slip rings it is problematic that the sliding contact cannot be maintained perfectly over a longer time span and at high rotation speeds of the rotor. The cause lies in the sliding movement of the brush fibers over the slideway since at least some of these temporarily stick to the slideway rather than sliding. If such slip rings are used in CT systems to acquire tomographic images, this means a data loss or an incorrect transfer of data sets can occur. In addition to the reduced quality of the data and current transfer, significant wear of the slideway and the brushes results from an incorrect sliding contact due to the mechanical movement between the components, and increased maintenance and cost expense result.